Solid propellant propulsion system



P 1951 R.- F. WENZEL ETAL 3,000,306

sou PROPELLANT PROPULSION SYSTEM Filed Jan. 9, 1958 FIG.

FIG. 2

23 22 INVENTORS ROBERT E WENZEL FIG. 4

CLARK E. ALLARDT United States Patent 3,000,306 SOLID PROPELLANT PROPULSION SYSTEM Robert F. Wenzel, West Covina, and Clark E. Allardt,

Pomona, Calif., assignors to General Dynamics Corporation, San Diego, Calif., a corporation of Delaware Filed Jan. 9, 1958, Ser. No. 707,959 3 Claims. (Cl. 102-49) The present invention relates to a solid propellant propulsion system, and more particularly to a propulsion system having a boost stage and a sustainer stage with a time delay between the two stages during which no thrust is produced.

This propulsion system is designed to permit the firing of a missile from a hand-carried launch tube. The system provides an initial high thrust followed by a short period of zero thrust. The initial thrust is to boost the missile out of the launcher. The zero thrust period is to protect the firing personnel from the rocket blast. The second thrust phase or sustainer phase beginswhen the missile has reached a safe distance from the launcher.

In most booster-sustainer configurations, the booster is separated from the missile and allowed to fall free. However, for missiles fired from a hand-carried launcher, such a system would create a hazard for friendly personnel.

In this invention the boost stage is retained by the missile and used to not only provide the initial forward acceleration of the missile but to provide the desired initial roll rate of the missile (all within the launch tube). Depending on the desired roll program, the missile may have canted or beveled fins to help maintain roll after the booster burns out. The boost charge and a plurality of boost nozzles are annularly arrangedabout the sustainer nozzle. The boost nozzles are canted to accelerate the missile up to the desired initial roll rate.

An object of the present invention is to provide a propulsion system which minimizes effects of rocket blast on missile firing personnel by having a period of zero thrust.

Another object is to provide a propulsion system which has a boost stage with canted nozzles to produce roll as well as forward thrust.

Other objects and features of the present invention will be readily apparent to those skilled in the art from the following specification and appended drawings wherein is illustrated a preferred form of the invention, and in which:

FIGURE 1 is a cross section of the propulsion system components as they would appear when incorporated in a missile.

FIGURE 2 is a side elevational view of a nozzle spool which forms part of the propulsion system.

FIGURE 3 is a rear view of the nozzle spool.

FIGURE 4 is a drawing illustrating how dual chamber ignition may be accomplished.

Referring to FIGURE 1, the cross section of the propulsion system shows the sustainer or main propellant charge 11. The boost charge 12 is shown positioned around the sustainer nozzle 13. The boost nozzles 14 are arranged about the sustainer nozzle in an annular manner. The boost nozzles and sustainer nozzle are part of a nozzle spool generally indicated by arrow 15.

The preferred embodiment shown in FIGURE 1 uses the cylindrical skin of the missile to complete the booster and sustainer chambers. This, however, is not a requirement. It is conceivable that the propulsion system could be enclosed in a cylinder within the missiles skin. Also, one of the chambers could be enclosed in a separate cylinder while the remaining chamber used the missiles skin as the enclosing surface. The configuration shown in FIGURE 1 is preferred because it is more efficient than others.

The nozzle spool 15 is shown in a plan view in FIG- URE 2. The grooves 16 and 17 seat ring seals which maintain the required chamber pressure in the boost and sustainer stages. The shank 18 of the spool contains the sustainer nozzle. The rear flange 21 of the spool contains the canted boost nozzles.

FIGURE 3 is a rear view of the nozzle spool whichshows how the boost nozzles are canted to produce missile roll. The amount of nozzle cant may be varied in accordance with the desired roll rate.

Ignition of the dual chamber configuration may be accomplished in a number of ways. The preferred meth-.

od is the simultaneous ignition of both motors from an external power source with a powder delay in the sustainer motor incorporated in the sustainer ignitor. Another method is the use of a sustainer powder delay with an arming device which functions only after the missile has traveled a certain distance in the launching tube. The arming device need only be a mechanism which blocks the powder train from the sustainer ignitor until actuated. Actuation could be accomplished through the side of the missileor possibly through the aft end of a nozzle with a trailing wire. Another method would be the use of a trailing wire to which electrical power is applied to the sustainer ignitor only after the missile has moved down the launching tube.

Still another method would be to have a hole in the nozzle spool 15 between the boost chamber and sustainer chamber. A powder train could be placed in this hole andwould ignite the sustainer after boost charge burn out. This would mean that, after booster burnout, there would be a bleed off the sustainer motor into the booster chamber unless the hole were plugged. This bleed, however, could be used to affect missile roll.

The preferred method of ignition is illustrated in FIG- URE 4. The ignitors 22 and 23 are ignited simultaneously by applying electrical power to terminal 25. The ignitor 22 ignites the boost charge and the ignitor 23 ignites the powder train 24. The boost charge burns out before clearing the launch tube and the powder train 24 will ignite the sustainer charge after the missile is a safe distance from the firing personnel.

Solid propellants suitable for use in this propulsion system are manufactured by the Atlantic Research Corporation, Aerojet, ABL and others.

While certain preferred embodiments of the invention have been specifically disclosed, it is understood that the invention is not limited thereto as many variation will be readily apparent to those skilled in the art and the invention is to be given its broadest possible interpretation within the terms of the following claims.

What we claim is:

1. A solid propellant propulsion system for use within a missile, said propulsion system comprising a missile housing, a solid fuel sustainer charge disposed within said missile housing, a sustainer exhaust nozzle positioned adjacent said sustainer charge, a solid fuel boost charge positioned about said sustainer exhaust nozzle and within said missile housing, meansfor igniting said sustainer charger, means for igniting said boost charge, a plurality of boost exhaust nozzles annularly arranged about said sustainer nozzle adjacent said boost charge, said boost exhaust nozzles being canted to provide force components acting both longitudinally and tangentially of said missile to produce missile roll as well as forward thrust, and means associated with said propulsion system through operative connection with said sustainer charge ignition means and said boost charge ignition means for delaying ignition of said sustainer charge by said sustainer charge ignition means to produce a period of substantially zero thrust between a first expenditure of said boost charge consequent to ignition by said boost charge ignition means and said ignition and subsequent expenditure of said sustainer charge.

2. A solid propellant propulsion system for use within a missile, said propulsion system comprising a missile housing of substantially longitudinal proportions and having a rear end portion and a forward end portion, a nozzle spool disposed in said housing, said spool having a shank and two end flanges with said shank lying longitudinally parallel to said housing and said flanges substantially dividing the interior of said housing into sections one of said flanges being a rear flange located substantially at said rear end portion of said missile housing and forming the rear of the propulsion system, the other of said flanges being spaced forward of said rear flange at the forward end of said shank, said shank containing a sustainer exhaust nozzle, said rear flange containing a plurality of boost exhaust nozzles annularly arranged about said sustainer exhaust nozzle, said boost exhaust nozzles being canted to produce missile roll as well as forward thrust, a solid fuel boost charge positioned about said shank and between said flanges, a solid fuel sustainer charge disposed forward of and adjacent to the forward flange of said nozzle spool, means for igniting said boost charge, means for igniting said sustainer charge, and means associated with said propulsion system through operative connection with said sustainer charge ignition means and said boost charge ignition means for delaying ignition of said sustained charge by said sustainer charge ignition means to produce a period of substantially zero thrust between a first expenditure of said boost charge consequent to ignition by said boost charge ignition means and said ignition and subsequent expenditure of said sustainer charge.

3. A solid propellant propulsion system for use within a missile, said propulsion system comprising a missile housing of substantially longitudinal proportions and having a rear end portion and a forward end portion, a

nozzle spool disposed in said housing, said spool having a shank and two end flanges with said shank lying longitudinally parallel to said housing and said flanges substantially dividing the interior of said housing into sections, one of said flanges being a rear flange located substantially at said rear end portion of said missile housing and forming the rear of the propulsion system, the other of said flanges being spaced forward of said rear flange at the forward end of said shank, said shank containing a sustainer exhaust nozzle, said rear flange containing a plurality of boost exhaust nozzles annularly arranged about said sustainer exhaust nozzle, said boost exhaust nozzles being canted to produce missile roll as well as forward thrust, a solid fuel boost charge positioned about said shank and between said flanges, a solid fuel sustainer charge disposed forward of and adjacent to the forward flange of said nozzle spool, a first ignitor disposed in said boost charge and a second ignitor disposed in said sustainer charge, said ignitors being electrically connected for simultaneous activation, said first ignitor initiating combustion of said boost charge, a powder train connected to said second ignitor and ignited thereby, said powder train having a pre-selected burning time and igniting said sustainer charge after expenditure of said boost charge and after a period of substantially zero thrust following expenditure of said boost charge.

References Cited in the file of this patent UNITED STATES PATENTS 2,524,591 Chandler ..g.,...-, Oct. 3, 1950 2,623,465 Jasse Dec. 30, 1952 2,724,237 Hickman Nov. 22, 1955 2,750,887 Marcus June 19, 1956 FOREIGN PATENTS 5,099 Great Britain Dec. 12, 1878 733,190 Great Britain Apr. 24, 1957 

1. A SOLID PROPELLANT PROPULSION SYSTEM FOR USE WITHIN A MISSILE, SAID PROPULSION SYSTEM COMPRISING A MISSILE HOUSING, A SOLID FUEL SUSTAINER CHARGE DISPOSED WITHIN SAID MISSILE HOUSING, A SUSTAINER EXHAUST NOZZLE POSITIONED ADJACENT SAID SUSTAINER CHARGE, A SOLID FUEL BOOST CHARGE POSITIONED ABOUT SAID SUSTAINER EXHAUST NOZZLE AND WITHIN SAID MISSILE HOUSING, MEANS FOR IGNITING SAID SUSTAINER CHARGER, MEANS FOR IGNITING SAID BOOST CHARGE, A PLURALITY OF BOOST EXHAUST NOZZLES ANNULARLY ARRANGED ABOUT SAID SUSTAINER NOZZLE ADJACENT SAID BOOST CHARGE, SAID BOOST EXHAUST NOZZLES BEING CANTED TO PROVIDE FORCE COMPONENTS ACTING BOTH LONGITUDINALLY AND TANGENTIALLY OF SAID MISSILE TO PRODUCE MISSILE ROLL AS WELL AS FORWARD THRUST, AND MEANS ASSOCIATED WITH SAID PROPULSION SYSTEM THROUGH OPERATIVE CONNECTION WITH SAID SUSTAINER CHARGE IGNITION MEANS AND SAID BOOST CHARGE IGNITIONMEANS FOR DELAYING IGNITION OF SAID SUSTAINER CHARGE BY SAID SUSTAINER CHARGE IGNITION MEANS TO PRODUCE A PERIOD OF SUBSTANTIALLY ZERO THRUST BETWEEN A FIRST EXPENDITURE OF SAID BOST CHARGE CONSEQUENT TO IGNITION BY SAID BOOST CHARGE IGNITION MEANS AND SAID IGNITION AND SUBSEQUENT EXPENDITURE OF SAID SUSTAINER CHARGE. 